Environmental classification controlled output level in bone conduction devices

ABSTRACT

A bone conduction device is configured to classify received sound signals (sounds) into one or more sound categories/classes (i.e., determine the input signal type). The bone conduction device is configured to dynamically set a maximum force output (MFO) of the bone conduction device at least based on the sound class of the sound signals.

BACKGROUND Field of the Invention

The present invention relates generally to bone conduction devices.

Related Art

Hearing loss, which may be due to many different causes, is generally oftwo types: conductive and sensorineural. Sensorineural hearing loss isdue to the absence or destruction of the hair cells in the cochlea thattransduce sound signals into nerve impulses. Various hearing prosthesesare commercially available to provide individuals suffering fromsensorineural hearing loss with the ability to perceive sound. Forexample, cochlear implants use an electrode array implanted in thecochlea of a recipient to bypass the mechanisms of the ear. Morespecifically, an electrical stimulus is provided via the electrode arrayto the auditory nerve, thereby causing a hearing percept.

Conductive hearing loss occurs when the normal mechanical pathways thatprovide sound to hair cells in the cochlea are impeded, for example, bydamage to the ossicular chain or ear canal. Individuals suffering fromconductive hearing loss may retain some form of residual hearing becausethe hair cells in the cochlea may remain undamaged.

Individuals suffering from conductive hearing loss typically receive anacoustic hearing aid. Hearing aids rely on principles of air conductionto transmit acoustic signals to the cochlea. In particular, a hearingaid typically uses an arrangement positioned in the recipient's earcanal or on the outer ear to amplify a sound received by the outer earof the recipient. This amplified sound reaches the cochlea causingmotion of the perilymph and stimulation of the auditory nerve.

In contrast to hearing aids, which rely primarily on the principles ofair conduction, certain types of hearing prostheses, commonly referredto as bone conduction devices, convert a received sound into vibrations.The vibrations are transferred through the skull to the cochlea causinggeneration of nerve impulses, which result in the perception of thereceived sound. Bone conduction devices are suitable to treat a varietyof types of hearing loss and may be suitable for individuals who cannotderive sufficient benefit from acoustic hearing aids, cochlear implants,etc., or for individuals who suffer from stuttering problem.

SUMMARY

In one aspect, a method is provided. The method comprises: receivingsound signals at a bone conduction device; determining a sound class ofthe sound signals; and dynamically setting a maximum force output (MFO)of the bone conduction device at least based on the sound class of thesound signals.

In another aspect, a method is provided. The method comprises: receivingsound signals at a bone conduction device located in an acousticenvironment, wherein the bone conduction device comprises an actuatorand at least one battery; assessing, based on the sound signals, theacoustic environment of the bone conduction device; determining, basedat least in part on the acoustic environment of the bone conductiondevice, an instantaneous amount of power that is available from the atleast one battery to other components of the bone conduction device;generating, based on the sound signals and the instantaneous amount ofpower that is available from the at least one battery to othercomponents of the bone conduction device, electrical signals for use indriving the actuator for delivery of mechanical force to tissue of auser of the bone conduction device; and driving the actuator with theelectrical signals.

In another aspect, a bone conduction device is provided. The boneconduction device comprises: one or more sound input elements configuredto receive sound signals; at least one battery; an actuator; anenvironmental classifier configured to determine a sound class of thesound signals; a sound processing module and amplifier configured toconvert the sound signals into one or more output signals for use indriving the actuator; and a controller configured to set, based on thesound class of the sound signals, a maximum peak battery power availableto the sound processing module and amplifier when generating the outputsignals.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are described herein in conjunctionwith the accompanying drawings, in which:

FIG. 1A is a perspective view of an exemplary bone conduction device inwhich at least some embodiments presented herein can be implemented;

FIG. 1B is a perspective view of an alternate exemplary bone conductiondevice in which at least some embodiments presented herein can beimplemented;

FIG. 2 is a functional block diagram of an embodiment of a boneconduction device, in accordance certain embodiments presented herein;

FIGS. 3A-3C are tables illustrating example average maximum forceoutputs (MFOs) for bone conduction devices, in accordance with certainembodiments presented herein;

FIGS. 4A-4C are tables illustrating example average MFOs for boneconduction devices, in accordance with certain embodiments presentedherein;

FIG. 5 is schematic diagram illustrating example inputs for a dynamicMFO adjustment process, in accordance with certain embodiments presentedherein;

FIG. 6 is a flowchart of a method, in accordance with certainembodiments presented herein; and

FIG. 7 is a flowchart of another method, in accordance with certainembodiments presented herein.

DETAILED DESCRIPTION

Presented herein are techniques in which a bone conduction device isconfigured to classify received sound signals (sounds) into one or moresound categories/classes (i.e., determine the input signal type). Thebone conduction device is configured to dynamically set a maximum forceoutput (MFO) of the bone conduction device at least based on the soundclass of the sound signals.

FIG. 1A is a perspective view of a bone conduction device 100A in whichcertain embodiments presented herein may be implemented. As shown, therecipient has an outer ear 101, a middle ear 102 and an inner ear 103.Elements of outer ear 101, middle ear 102 and inner ear 103 aredescribed below, followed by a description of bone conduction device100A.

In a fully functional human hearing anatomy, outer ear 101 comprises anauricle 105 and an ear canal 106. A sound wave or acoustic pressure 107is collected by auricle 105 and channeled into and through ear canal106. Disposed across the distal end of ear canal 106 is a tympanicmembrane 104 which vibrates in response to acoustic wave 107. Thisvibration is coupled to oval window or fenestra ovalis 110 through threebones of middle ear 102, collectively referred to as the ossicles 111and comprising the malleus 112, the incus 113 and the stapes 114. Theossicles 111 of middle ear 102 serve to filter and amplify acoustic wave107, causing oval window 110 to vibrate. Such vibration sets up waves offluid motion within cochlea 139. Such fluid motion, in turn, activateshair cells (not shown) that line the inside of cochlea 139. Activationof the hair cells causes appropriate nerve impulses to be transferredthrough the spiral ganglion cells and auditory nerve 116 to the brain(not shown), where they are perceived as sound.

FIG. 1A also illustrates the positioning of bone conduction device 100Arelative to outer ear 101, middle ear 102 and inner ear 103 of arecipient of device 100. As shown, bone conduction device 100 ispositioned behind outer ear 101 of the recipient and comprises one ormore sound input devices 126 to receive sound signals. The sound inputelements may comprise, for example, a microphone, telecoil, etc. In anexemplary embodiment, sound input element 126 is a microphone located,for example, on or in bone conduction device 100A. Alternatively, themicrophone 126 could be located on a cable extending from boneconduction device 100A, physically separated from the bone conductiondevice (e.g., an in-the-ear microphone in wireless communication withthe bone conduction device), etc.

In an exemplary embodiment, bone conduction device 100A is anoperationally removable component configured to be releasably coupled toa bone conduction implant (not shown in FIG. 1A). That is, the boneconduction device 100A can be attached/detached to/from the boneconduction implant by the recipient (or other user) during normal use ofthe bone conduction device 100A. Such releasable coupling isaccomplished via a coupling assembly 140 that is configured tomechanically mate with the bone conduction implant.

The bone conduction device 100A includes a housing 125A in which a soundprocessing module, an actuator/transducer, amplifier, controller, and/orvarious other electronic circuits/devices are positioned. The actuatormay comprise, for example, a vibrating electromagnetic actuator, avibrating piezoelectric actuator, or another type of actuator. Inoperation, the microphone 126 (e.g., microphone) converts received soundsignals into electrical signals. These electrical signals are processedby the sound processing module. The sound processing module generatescontrol signals which cause the actuator to vibrate. In other words, theactuator converts the electrical signals into mechanical motion toimpart vibrations to the recipient's skull. As such, the bone conductiondevice 100A is sometimes referred to as a “vibrator unit” or “vibrator,”since it generates vibration for delivery to the skull of the recipient.

As shown in FIG. 1A, the bone conduction device 100A further includes acoupling assembly 140 configured to be removably attached to the boneconduction implant (sometimes referred to as an anchor system and/or afixation system) implanted in the recipient. In the embodiment of FIG.1A, the bone conduction implant includes a percutaneous abutmentattached to a bone fixture via a screw, where the bone fixture is fixedto the recipient's skull bone 136. The abutment extends from the bonefixture which is screwed into bone 136, through muscle 134, fat 128 andskin 232 so that the coupling assembly 140 may be attached thereto. Sucha percutaneous abutment provides an attachment location for the couplingassembly that facilitates efficient transmission of mechanical force(vibration) generated by the bone conduction device 100A. Due to the useof the percutaneous abutment, the bone conduction device 100A issometimes referred to as a “percutaneous bone conduction device.”

Although FIG. 1A illustrates a percutaneous bone conduction device 100A,it is to be appreciated that certain aspects presented herein may beutilized with other types of bone conduction devices. For example, FIG.1B is a perspective view of a “transcutaneous bone conduction device”100B in which embodiments presented herein can be implemented. Asdescribed further below, a transcutaneous bone conduction device is abone conduction device that does not use a percutaneous abutment.Instead, the transcutaneous bone conduction device is held against theskin via a magnetic coupling (e.g., magnetic material and/or magnetsbeing implanted in the recipient and the vibrator having a magnet and/ormagnetic material to complete the magnetic circuit, thereby coupling thevibrator to the recipient).

More specifically, FIG. 1B also illustrates the positioning oftranscutaneous bone conduction device 100B relative to outer ear 101,middle ear 102 and inner ear 103 of a recipient of device 100. As shown,bone conduction device 100B is positioned behind outer ear 101 of therecipient and comprises a housing 125B having a microphone 126positioned therein or thereon. Disposed in housing 125B is a magneticcomponent, a sound processing module, an actuator (e.g., electromagneticactuator, piezoelectric actuator, etc.), amplifier, and/or various otherelectronic circuits/devices are positioned. Similar to bone conductiondevice 100A of FIG. 1A, in FIG. 1B the microphone 126 (e.g., microphone)converts received sound signals into electrical signals. Theseelectrical signals are processed by the sound processing module. Thesound processing module generates control signals which cause theactuator to vibrate. In other words, the actuator converts theelectrical signals into mechanical motion to impart vibrations to therecipient's skull.

In accordance with the embodiment of FIG. 1B, a fixation system 144 maybe used to secure an implantable component 142 to skull 136. Asdescribed below, fixation system 144 may be a bone screw fixed to skull136, and also attached to implantable component 142.

In the arrangement of FIG. 1B, the bone conduction device 100B is apassive transcutaneous bone conduction device. That is, no activecomponents, such as the actuator, are implanted beneath the recipient'sskin 132. Instead, the active actuator is located in bone conductiondevice 140B and the implantable component 142 includes a magnetic plate.The magnetic plate of the implantable component 142 vibrates in responseto vibrations transmitted through the skin, mechanically and/or via amagnetic field, that are generated by the magnetic component (plate) inthe bone conduction device 100B.

Collectively, FIGS. 1A and 1B illustrate two arrangements of boneconduction devices in which embodiments presented herein may beimplemented. However, it is to be appreciated that the embodiments shownin FIGS. 1A and 1B are merely illustrative and that the techniquespresented herein may be used in other arrangements. For example, thetechniques presented herein could also or alternatively be implementedwith “active transcutaneous bone conduction devices” where the actuatoris implanted within the recipient (e.g., in implantable component 142).In such arrangements, the a sound processing module may be disposed inan external component and electrical signals representative of theprocessed sound signals are transcutaneously sent to the implantablecomponent for use in driving the actuator and, as such, generatingvibration for delivery to the recipient.

In general, FIGS. 1A and 1B illustrate that bone conduction devices areconfigured to receive and process sound signals, and to use those soundsignals to generate vibrations for delivery to the recipient. FIGS. 1Aand 1B correspond to percutaneous and transcutaneous mechanisms,respectively, for delivery of the vibrations to the recipient. FIG. 2 isa functional block diagram illustrating further details regarding howsound signals are used to generate vibrations for delivery to therecipient, in accordance with certain embodiments presented herein.

More specifically, shown in FIG. 2 is a bone conduction device 200mechanically or magnetically coupled to a bone conduction implant 246(representing a percutaneous or transcutaneous vibration deliverymechanism). Bone conduction device 200 comprises a housing 225 and oneor more sound input devices, namely microphones 226, disposed in or onthe housing 225. The bone conduction device 200 may include additionalsound input devices which, for ease of illustration, have been omittedfrom FIG. 2 .

The bone conduction device 200 also comprises a sound processing module250, an amplifier 252, an actuator 254, an environmental classifier 256,a controller (control circuit) 258, at least one battery 260, and aninterface module 262. In operation, the microphone(s) 226 are configuredto receive sound signals (sound) 207, and to convert the received sound207 into electrical signals 222. If other sound input devices arepresent, the sound 207 could also or alternatively may be received by asan electrical signal.

As shown in FIG. 2A, electrical signals 222 are output by microphone 226to a sound processing module 250. The sound processing module 250 isconfigured to convert the electrical signals 222 into adjusted/processedelectrical signals 224. That is, the sound processing module 250 isconfigured to apply one or more processing operations (e.g., filtering,noise reduction, automatic gain control/adjustment, loudnesscompression, etc.) to the electrical signals 222. In certainembodiments, the sound processing module 250 may include a digitalsignal processor.

The processed electrical signals 224 are provided to the amplifier 252.The amplifier 252 amplifies (i.e., increases the time-varying voltage orcurrent) the processed electrical signals 224 to generate amplifiedoutput signals 230. The amplified output signals 230 are then used todrive (activate) the actuator 254 which, in turn, generatescorresponding vibrations. That is, using the amplified output signals230, the actuator 254 generates a mechanical output force that isdelivered to the skull of the recipient via bone conduction implant 246.Delivery of this output force causes one or more of motion or vibrationof the recipient's skull, thereby activating the hair cells in thecochlea via cochlea fluid motion and, in turn, evoking perception by therecipient of the received sound signals 207.

As noted, bone conduction device 200 comprises at least one battery 260.The at least one battery 260 provides electrical power to the variouscomponents of bone conduction device 200. For ease of illustration,battery 260 has been shown connected only to controller 258. However, itshould be appreciated that battery 260 may be used to supply power toany electrically powered circuits/components of bone conduction device200, including sound processing module 250, amplifier 252, actuator 254,etc.

Bone conduction device 200 further includes the interface module 262that allows the recipient or other user to interact with device 200. Forexample, interface module 262 may allow the recipient to adjust thevolume, alter the speech processing strategies, power on/off the device,etc. Again, for ease of illustration, interface module 262 has beenshown connected only to controller 258.

In the embodiment illustrated in FIG. 2 , the components (e.g.,microphone 226, actuator 254, etc.) have all been shown as integratedinto a single housing, referred to as housing 225. However, it should beappreciated that in certain embodiments of the present invention, one ormore of the illustrated components may be housed in separate ordifferent housings. Similarly, it should also be appreciated that insuch embodiments, direct connections between the various modules anddevices are not necessary and that the components may communicate, forexample, via wireless connections.

A bone conduction device, such as bone conduction device 200, operatesin accordance with a number of different parameters. One such parameteris the Maximum Force Output (MFO) of the bone conduction device 200. Asused herein, MFO refers to the maximum allowable output that the boneconduction device 200 can produce For bone conduction devices, MFO ismeasured in dB relative to one micro Newton of force (dB rel. 1 μN). Forease of description, the techniques presented herein will be describedwith reference to the MFO of bone conduction device 200.

It is to be understand that, as used herein, the MFO is specificallytied to the peak power/energy that can be drawn from thebattery/batteries of the bone conduction device at a given time. Thatis, the MFO specifically corresponds to the instantaneous amount ofpower that is available, from the device battery/batteries, to othercomponents of the bone conduction device when generating vibration fordelivery to the recipient. Therefore, as described further below,dynamically increasing the MFO refers to dynamically increasing theamount of battery power that is available to one or more components ofthe bone conduction device, when generating vibration for delivery tothe recipient. Accordingly, when more battery power is made available,the output(s) generated by the bone conduction device may be higher.

It is also to be understood that the MFO refers to the maximum“allowable” output that a bone conduction device produces. The MFO, evenwhen increased as described further below, would still be below themaximum capabilities of the device components themselves (i.e., MFO doesrefer to the levels/points at which components of the device will beginto fail, but is set below such failure levels).

Moreover, it is to be understood that the MFO of a bone conductiondevice is separate and distinct from any gain adjustments in the boneconduction device. More specifically, the sound processing modules ofbone conduction devices may include dynamic or automatic gain control,which operates as regulating circuit for the amplifier(s). The purposeof the gain control is to maintain a suitable signal amplitude at itsoutput, despite variation of the signal amplitude at the input. Forexample, in one arrangement, the average or peak output signal level isused to dynamically adjust the gain of the amplifiers, enabling thecircuit to work satisfactorily with a greater range of input signallevels. Although these gain adjustments may affect the levels of theoutputs generated by the bone conduction device, such adjustments arenot related to the allowable maximum levels of battery power that wouldbe available for use. Instead, any gain adjustments are performed withinthe framework of whatever MFO is currently set for a bone conductiondevice (i.e., the MFO acts as a control for the gain adjustments). Inone example, increasing the MFO of a bone conduction device couldpotentially enable the automatic gain control to increase the outputsignals levels, although the inverse is not true (i.e., increasing thegain does not increase, nor does it affect, the MFO of the boneconduction device).

MFO is important as it sets the dynamic range that a bone conductiondevice can provide to a recipient. There are two types of dynamic range,namely that of the amplifier 252 and that of recipient's hearing. Withamplifier 252, the dynamic range is defined as the difference betweenthe smallest amplified intensity and the loudest output of theamplifier. For human hearing, the dynamic range is defined as thedifference between the softest sound heard and sounds that areuncomfortably loud.

Normal hearing individuals can have dynamic ranges of 100 dB or more,meaning the softest sound they can hear and the point at which soundbecomes uncomfortably loud can range up to 100 dB. Sensorineural hearingloss and conductive hearing loss may affect this dynamic range indifferent ways. For example, with sensorineural hearing loss, therecipient's thresholds are increased (meaning sound has to be louderbefore they can hear it), but their loudness tolerance is either thesame or can be decreased, leading to an overall reduction in dynamicrange. This must be addressed when fitting amplification, usually bycompressing the amplifier's dynamic range to accommodate the patient'simpaired range of hearing. With conductive hearing loss, the recipient'sthresholds are increased, as it is with sensorineural hearing loss, buttheir loudness tolerance is also increased, mostly preserving thedynamic range.

Therefore, while a recipient with sensorineural hearing loss may requiremore gain for soft sounds and less or no gain for loud sounds, arecipient with conductive hearing loss will require similar gain forsoft, moderate and loud sounds (i.e., linear amplification). This meanssomeone with a conductive component to their hearing loss may require amuch higher output than someone with sensorineural hearing loss andtherefore a bone conduction device with a large dynamic range.

Generally, the need for additional power in a normal hearing aid (i.e.,for sensorineural loss) is relatively small because the hearing aid onlydrives the tympanic membrane. In contrast, .due to the operationalnature of bone conduction devices (i.e., inducing vibration of arecipient's heavy skull) and the need to keep the devices reasonablysmall, is more difficult to achieve high output levels in boneconduction devices (i.e., vibrating the whole skull is much more energydemanding than simply driving the tympanic membrane). Additionally, whena bone conduction device operates at/with a higher MFO, the result ishigh power consumption, when compared to operation at a lower MFO.

Bone conduction devices generally operate using power supplied by atleast one battery disposed in the device. Bone conduction devices maytraditionally been powered by disposable batteries, such as Zinc-airbatteries, which generally have a limited peak (instantaneous) powercapability. Therefore, operation of bone conduction devices havingdisposable batteries at a higher MFO presents a risk for an unexpectedshutdown of the bone conduction device (i.e., because more instantaneouspower is drawn from the battery). For hearing impaired recipients,unexpected shutdowns are not only problematic, but also potentiallydangerous.

More recently, rechargeable batteries, such as lithium-ion (Li-ion)batteries, have been proposed for use in bone conduction devices. Whilea disposable battery is typically able to power a bone conduction devicefor several days, most rechargeable batteries have a limited totalenergy per volume which results in a shorter operational life whencompared to disposable batteries. Despite the limited total energy pervolume, and the battery size restraints associated with bone conductiondevices, the expectation is that a rechargeable battery should be ableto power the bone conduction device for a full day of use by therecipient (e.g., 14 hours, 16 hours, etc.). As noted, operation of boneconduction devices with a higher MFO increases the power consumption ofthe device which, in turn, can further shorten the operational life ofbone conduction devices with rechargeable batteries. With rechargeablebatteries, this is particularly problematic since the reducedoperational life could leave the recipient without an operational boneconduction device during the day.

In summary, operation of bone conduction devices with a higher MFO canimprove the recipient's sound perception. However, there is asignificant power consumption cost associated with operating a boneconduction device at such high output levels, which could causeunexpected shutdowns or decrease the operating life of the device. As aresult, conventional bone conduction devices may simply limit the boneconduction device output level to a pre-determined/fixed MFO (e.g.,determined at the time of fitting) that ensures an acceptable batterylife and/or that prevents unexpected shutdown. However, by artificiallyreducing the MFO of the bone conduction device, such conventional boneconduction devices inherently limit the hearing performance that can beachieved by the bone conduction device. Accordingly, presented hereinare techniques that balance the improved hearing performance provided byhigh output levels (i.e., operation at a higher MPO) with powerconsumption/battery life limitations. In particular, the techniquespresented herein provide a bone conduction devices with a dynamic MFOadjustments, where the MFO of the bone conduction device can be set, inreal-time, based on parameters of the received sound signals, such asthe sound class/environment associated with the sound signals.

More specifically, returning to the specific example of FIG. 2 , thebone conduction device 200 includes an environmental classificationmodule (environmental classifier) 256. As shown, the environmentalclassifier 256 receives the electrical signals 222 output by themicrophone(s) 226. Using these electrical signals, the environmentalclassifier 256 is configured to evaluate/analyze the received soundsignals (sounds) 207 and determine the sound class/category/environmentof the sounds. That is, the environmental classifier 256 is configuredto use the received sounds to “classify” the ambient sound environmentand/or the sounds into one or more sound categories (i.e., determine theinput signal type). The sound class or environment may include, but arenot limited to, “Speech” (e.g., the sound signals include primarilyspeech signals), “Noise” (e.g., the sound signals include primarilynoise signals), “Speech+Noise” (e.g., both speech and noise are presentin the sound signals), “Wind” (e.g., e.g., the sound signals includeprimarily wind signals), “Music” (e.g., the sound signals includeprimarily music signals), and “Quiet” (e.g., the sound signals includeminimal speech or noise signals). The environmental classifier 256 mayalso estimate the signal-to-noise ratio (SNR) of the sounds. In oneexample, the environmental classifier 256 generates sound classificationinformation/data 238. The sound classification data 238 represents thesound class of the sound signals and, in certain examples, the SNR ofthe sound signals.

As noted, bone conduction device 200 also comprises controller 258. Thecontroller 258 is configured to use the sound classification data 238(e.g., indicating the sound class of the sound signals) to determinewhether the bone conduction device 200 is in a listening environment inwhich the recipient could benefit from a higher output. In suchenvironments, the controller 258 is configured to dynamically adjustoperation of the bone conduction device 200 to temporarily increase theMFO of the bone conduction device (i.e., the controller 258 isconfigured to set, based on the sound class of the sound signals, amaximum peak battery power available to the sound processing module andamplifier when generating the amplified output signals 230).

That is, certain sound classes may benefit from the generation ofvibrations with using a higher MFO (e.g., Music, Speech,speech-in-noise), while others (e.g., Wind, Noise, Quiet) may not. Forexample, in a “Quiet” environment, there would be no effect of adjustingthe MFO since the sound levels are already low and there would be noaudible improvements or any power consumption effect. If the controller258 determines that the sound class of the sound signals matches a soundclass that can benefit from a higher MFO, then the controller 258 canmake corresponding adjustments to various parameters, settings,operations, etc. of the bone conduction device to dynamically achievethe higher MFO. That is, based on the sound class of the received soundsignals, the controller 258 enables, in real-time, components of thebone conduction device 200 (e.g., sound processing module 250, amplifier252, etc.) to temporarily draw/consume an increased amount of peakpower/energy from the at least one battery 260 while generatingamplified output signals 230 and, accordingly, the vibration fordelivery to the recipient. Therefore, dynamically increasing the MFOrefers to dynamically increasing the amount of battery power that isavailable to one or more components of the bone conduction device 200,when generating vibration for delivery to the recipient.

In certain bone conduction devices, the power available to the amplifieris constant (i.e., there is a constant voltage level available at theamplifier). Therefore, in such embodiments, the MFO can be dynamicallyadjusted by increasing or decreasing the output compression (e.g., MFOis lowered by setting the output compression to a lower level). The neteffect is lower power consumption (e.g., 3 dB lower, 50% less powerconsumption). Alternative strategies are possible where the availabledriving voltage to the amplifier is adjusted or even a differentamplifier running at a different (e.g., higher or lower) voltage levelis used instead.

In certain embodiments, the MFO (i.e., available battery power) may beincreased in response to specific sound parameters (e.g., sound class,signal-to-noise ratio (SNR), etc.) for a predetermined period of time,until the environmental classifier 256 detects a different sound class,etc. As described further below, the determination of whether toincrease the MFO, or whether to terminate the use of an increased MFO,may be further based on one or more operational parameters of the boneconduction device 200, such as a status (e.g., charge level) of the atleast one battery 260.

Adjustment to one or more parameters, settings, operations, etc. of thebone conduction device 200 by the controller 258 to achieve a higher MFOis schematically represented in FIG. 2 by arrows 246 (i.e., between thecontroller 258 and each of the sound processing module 250, he amplifier252, and the at least one battery 260). However, is to be appreciatedthat adjustments to other components/elements of bone conduction device200 to achieve a temporarily higher MFO are also possible.

In summary, the techniques presented herein link the environmentclassifier 256 to the MFO control to allow for the higher outputs onlyin situations where the increased output would be the most beneficial tothe hearing rehabilitation of the recipient. That is, an increased MFOis only used in certain sound environments (i.e., certain soundclasses). In certain embodiments, the increased MFO may be used only inenvironments in which speech is present (i.e., “Speech” classification)or only sound environments in which speech and noise are both present(i.e., “Speech+Noise” classification). It is to be appreciated that, incertain embodiments, the environments in which the increased MFO is usedcould be customized based on recipient preferences. For example, arecipient who is a passionate music listener may alternatively preferthat the increased MFO is also or alternatively used when music ispresent (i.e., “Music” classification).

FIGS. 3A-3C are tables illustrating example average MFOs for boneconduction device 200 for different sound classes, in accordance withcertain embodiments presented herein. In FIGS. 3A-3C, the MFOs areexpressed in dB rel. to 1 μN. Also, the MFOs are referred to as“averages,” because, in practice, the MFOs can vary across frequency forthe device (i.e., different MFOs may be achievable for sound signals at500 Hertz (Hz), than for sound signals at 4000 Hz). It is to beappreciated that the MFOs shown in FIGS. 3A-3C are merely illustrativeand that bone conduction devices in accordance with embodimentspresented herein may, in practice, utilize different MFOs than thoseshown.

FIG. 3A illustrates an example in which an increased MFO is used onlywhen the environmental classifier 256 classifies the sounds 207 as“Speech+Noise” (i.e., both speech and noise are present in the soundenvironment). In this example, a standard/default MFO is used in allother sound classes (i.e., “Speech,” “Noise,” “Wind,” “Music,” and“Quiet”).

FIG. 3B illustrates an example in which an increased MFO is used onlywhen the environmental classifier 256 classifies the sounds 207 as“Speech+Noise” (i.e., both speech and noise are present in the soundenvironment) or when the environmental classifier 256 classifies thesounds 207 as “Music” (i.e., music is present in the sound environment).In this example, a standard/default MFO is used in all other soundclasses (i.e., “Speech,” “Noise,” “Wind,” and “Quiet”).

FIG. 3C illustrates an example in which increased MFOs are used in threedifferent sound classes. More specifically, in this example, astandard/default MFO is used in several sound classes (i.e., “Noise,”“Wind,” and “Quiet”). A first increased MFO is used when theenvironmental classifier 256 classifies the sounds 207 as “Speech,” anda second increased MFO is used when the environmental classifier 256classifies the sounds 207 as “Music.” A third increased MFO is used whenthe environmental classifier 256 classifies the sounds 207 as“Speech+Noise.”

As noted above, the MFO of the bone conduction device 200 may beincreased based on the current/present sound environment of the boneconduction device. In certain embodiments, the MFO of the boneconduction device 200 may be increased based on the current/presentsound environment and based one or more other parameters of the soundsignals. For example, the decision regarding whether to increase the MFOof the bone conduction device 200 may also be based on thesignal-to-noise ratio (SNR) of the sounds 207. In such examples, the MFOof the bone conduction device 200 is increased only in certain soundclasses, and only when the SNR is below a certain threshold (i.e., whenthe sound classification data 238 indicates a certain class of the soundsignals and specific SNRs).

FIGS. 4A-4C are tables illustrating example average MFOs for boneconduction device 200 for different sound classes and different SNRs, inaccordance with certain embodiments presented herein. Similar to FIGS.3A-3C, the MFOs in FIGS. 4A-4C are average values expressed in decibelsHearing Level (dB HL). Again, it is to be appreciated that the MFOs andSNRs shown in FIGS. 4A-4C are merely illustrative and that boneconduction devices in accordance with embodiments presented herein may,in practice, utilize different MFOs or SNR thresholds than those shown.

FIG. 4A illustrates an example in which an increased MFO is used onlywhen the environmental classifier 256 classifies the sounds 207 as“Speech+Noise” (i.e., both speech and noise are present in the soundenvironment) and when the SNR of the sounds 207 are below apredetermined threshold of 6 dB. In this example, a standard/default MFOis used in all other sound classes (i.e., “Speech,” “Noise,” “Wind,”“Music,” and “Quiet”), regardless of the SNR of the associated sounds207.

FIG. 4B illustrates an example in which an increased MFO is used whenthe environmental classifier 256 classifies the sounds 207 as“Speech+Noise” (i.e., both speech and noise are present in the soundenvironment) and when the SNR of the sounds 207 are below apredetermined threshold of 6 dB. Additionally, an increased MFO is usedwhen the environmental classifier 256 classifies the sounds 207 as“Music” (i.e., music is present in the sound environment) and when theSNR of the sounds 207 are below a predetermined threshold of 6 dB. Inthis example, a standard/default MFO is used in all other sound classes(i.e., “Speech,” “Noise,” “Wind,” and “Quiet”), regardless of the SNR ofthe associated sounds 207.

FIG. 3C illustrates an example in which increased MFOs are used in threedifferent sound classes and with different SNR thresholds. Morespecifically, in this example, a standard/default MFO is used in severalsound classes (i.e., “Noise,” “Wind,” and “Quiet”), regardless of theSNR of the associated sounds 207. A first increased MFO is used when theenvironmental classifier 256 classifies the sounds 207 as “Speech” andwhen the SNR of the sounds 207 are below a first predetermined thresholdof 6 dB. A second increased MFO is used when the environmentalclassifier 256 classifies the sounds 207 as “Music” and when the SNR ofthe sounds 207 are below a second predetermined threshold of 9 dB. Athird increased MFO is used when the environmental classifier 256classifies the sounds 207 as “Speech+Noise” and when the SNR of thesounds 207 are below a third predetermined threshold of 10 dB.

As noted above, the use of an increased MFO improves the recipient'shearing performance. However, the use of an increased MFO is alsoassociated with increased power consumption that could to an undesirablyshorten run-time of the bone conduction device 200 and/or unexpectedshutdown of the bone conduction device. Therefore, to prevent unexpectedshutdowns and/or to ensure an acceptable run-time of the bone conductiondevice 200, the controller 258 may base the determination of whether todynamically increase the MFO, or whether to terminate the use of anincreased MFO, not only on the sound parameters (i.e., attributes of thereceived sounds 207, such as sound class, SNR, etc.), but also furtherbased on one or more operational parameters of the bone conductiondevice 200. In certain embodiments, these operation parameters includebattery information/data 264 that the controller 258 obtains from the atleast one battery 260.

For example, the controller 258 may be configured to monitor a chargelevel of the battery 260 using the battery information 264. If thebattery information 264 indicates that the charge level of the battery260 is below a certain threshold level, the controller 258 may determinethat the MFO should not be increased, or that the use of an increasedMFO should be terminated, regardless of the current sound class, SNR,etc. That is, in this example, the MFO of the bone conduction device isset (i.e., either left at the default level or dynamically increased) atleast based on the sound class of the sound signals and the charge levelof the battery 260.

Additionally, in order to balance the need for high output with the riskof an empty battery before the end of the day, the controller 258 maybase the determination of whether to increase the MFO, or whether toterminate the use of an increased MFO, not only on the sound parameters(i.e., attributes of the received sounds 207, such as sound class, SNR,etc.), but also further based on auxiliary operational data 266. Thisauxiliary operational data may include, for example, time-of-day (ToD)information/data (e.g., information indicating the current time),location information/data (e.g., information, such as Global PositioningSystem (GPS) data, indicating the current physical location of the boneconduction device), calendar information (e.g., information obtain froman electronic calendar associated with a recipient), recipient habitinformation (e.g., learning the recipient's normal/typical habits fordifferent days), etc. These auxiliary operational data may be generatedby the controller 258 or obtained from one or more components disposedin, or connected to (e.g., in wireless communication with), the boneconduction device 200.

In one auxiliary operational data example, the environmental classifier256 could determine that the recipient is in a “Speech+Noise” soundenvironment, which could warrant an increased MFO. However, thecontroller 258 determines that the recipient typically goes to bed at10:00 PM, at which time the battery 260 is set to recharge. In thisexample, the controller 258 also determines that the current ToD is 9:00PM, and that the recipient is current located at his/herworkplace/business. Based on this auxiliary operational data, thecontroller 258 determines that the recipient will likely not be going tobed at the normal time (e.g., 10:00 PM) and, as such, the life ofbattery 260 needs to be extended beyond that which is normal. Therefore,the controller 258 determines that, to ensure that the bone conductiondevice 200 continues to operate, the controller 250 precludes the use ofan increased MFO even though the recipient is in a “Speech+Noise” soundenvironment. It is to be appreciated that this specific example ismerely illustrative of one technique for using auxiliary operationaldata with sound classification data 238 to set the MFO (e.g., determinewhether to increase the MFO, or whether to terminate the use of anincreased MPO), in accordance with embodiments presented herein.

In certain contexts of FIG. 2 , the controller 258 is described asperforming a real-time or dynamic MFO adjustment process. As describedabove, the dynamic MFO adjustment process is based on the soundparameters 238, mainly the sound classification data, but may also bebased on additional data. FIG. 5 is schematic diagram illustratingexample inputs for the dynamic MFO adjustment process, including thesound parameters 238, battery data 264, and auxiliary operational data266.

For ease of description, the embodiments of FIG. 2-5 have generally beendescribed with reference to “average” MFOs for bone conduction device200. However, it is to be appreciated that, in certain arrangements, theincreased MFOs may not be averages, but instead the increased MFOs areselected/tailored for specific frequency ranges of sounds.

More specifically, the sound processing module 250 may include aplurality of band-pass filters, represented in FIG. 2 by dashed box 268,configured to filter the electrical signals 222 (i.e., the sounds) intoa plurality of frequency components/bins, sometimes referred to asband-pass filtered signals (i.e., each band-pass filtered signal isassociated with a specific frequency range of the sound signals). Insuch embodiments, the sound processing module 250 produces a pluralityof adjusted/processed electrical signals 224 that each correspond to aspecific frequency range of the received sounds 207. Each of theplurality of processed electrical signals 224 are then amplified atamplifier 252, resulting in a plurality of amplified output signals 230that are used to drive actuator 254. In certain embodiments, the MFO ofthe bone conduction device 200 may be the same across the differentfrequencies or the MFO of the bone conduction device 200 may be setdifferently for different frequency bins (i.e., differently fordifferent amplified signals 230)

For example, the speech portion of sound signals generally includes themost energy in the lower frequencies. Additionally, depending on thetype of bone conduction device (e.g., electromagnetic actuator orpiezoelectric actuator), most of the power loss may occur at either thehigher or lower frequencies. Therefore, in order to effectively balancepower consumption and increased MFO, the MFO may be set differently inthe higher and/or lower different frequency regions. In the case of abone conduction device with an electromagnetic actuator, theelectromagnetic actuator will consume power mostly in the lowfrequencies. As such, in order to reduce power consumption, the MFO maybe set lower in the low frequency regions, but higher in the highfrequency regions because the power loss is not uniform acrossfrequency.

Therefore, in summary, the MFO adjustment techniques presented hereincould be implemented in a frequency-independent manner where the MFO isincreased for specific sound environments, regardless of frequency.Alternatively, the MFO adjustment techniques presented herein could beimplemented in a frequency-dependent manner where the MFO is increasedfor specific sound environments and only for specific frequencies ofsounds, or the MFO can be increased differently for differentfrequencies in the specific sound environments. In terms of the dynamicMFO adjustment process, the frequency of the sound signals can viewed asa sound parameter 238.

FIG. 2 illustrates an embodiment in which the increased MFO (ability forextra output) is built into the device as default. In an alternativeembodiment, a bone conduction device could be configured with a special“high power mode” using, for example, an auxiliary amplifier that ismore powerful than the amplifier used during normal operation. It may beundesirable to use such a powerful amplifier during all operation sincethe auxiliary amplifier could require increased static powerconsumption, provide inferior sound quality in quiet environments, etc.An auxiliary amplifier is generally represented in FIG. 2 by dashed box270. It would be appreciated that, if present, this auxiliary amplifier270 could be activated and used to generate the amplified output signals230 using switching and other circuitry that, for ease of illustration,have been omitted from FIG. 2 .

FIG. 6 is a flowchart of a method 680, in accordance with embodimentspresented herein. Method 680 begins at 682 where sound signals (sounds)are received at one or more sound input devices of a bone conductiondevice. At 684, the bone conduction device determines a sound class ofthe sound signals. At 686, a maximum force output (MFO) of the boneconduction device is set at least based on the sound class of the soundsignals.

FIG. 7 is a flowchart of another method 790, in in accordance withembodiments presented herein. Method 790 begins at 792 where soundsignals are received at a bone conduction device located in an acousticenvironment, wherein the bone conduction device comprises an actuator.At 794, the acoustic environment of the bone conduction device isassessed based on the sound signals. At 796, based at least in part onthe acoustic environment of the bone conduction device, an instantaneousamount of power that is available from the at least one battery to othercomponents of the bone conduction device is determined. At 798, based onthe sound signals and the instantaneous amount of power that isavailable from the at least one battery to other components of the boneconduction device, electrical signals for use in driving the actuatorfor delivery of mechanical force to tissue of a user of the boneconduction device are determined. At 799, the actuator is driven withthe electrical signals.

As noted above, presented herein are bone conduction devices that areconfigured to use the classification (class) of the sound signals todetermine whether the bone conduction device is located in a listeningenvironment in which the recipient could benefit from a higher output.When the bone conduction device is located in a listening environment inwhich the recipient could benefit from a higher output, the boneconduction device is configured to generate vibration for delivery to arecipient using a higher maximum force output (MFO) than which is usedin other listening environments. The techniques presented herein may beimplemented in a number of different types of bone conduction devices,including percutaneous bone conduction devices, transcutaneous boneconduction devices, active transcutaneous bone conduction devices,vibrating behind-the-ear (BTE) units, vibrating headphones, etc.

It is to be appreciated that the embodiments presented herein are notmutually exclusive.

The invention described and claimed herein is not to be limited in scopeby the specific preferred embodiments herein disclosed, since theseembodiments are intended as illustrations, and not limitations, ofseveral aspects of the invention. Any equivalent embodiments areintended to be within the scope of this invention. Indeed, variousmodifications of the invention in addition to those shown and describedherein will become apparent to those skilled in the art from theforegoing description. Such modifications are also intended to fallwithin the scope of the appended claims.

1.-20. (canceled)
 21. A method comprising: receiving ambient environmentsignals at a bone conduction device; determining a present soundenvironment based on the ambient environment signals; and dynamicallysetting a maximum force output (MFO) of the bone conduction device atleast based on loudness of the present sound environment.
 22. A Themethod of claim 21, wherein determining the present sound environmentcomprises: determining a present sound class based on the ambientenvironment signals, and wherein dynamically setting the MFO of the boneconduction device comprises: dynamically setting the MFO based on thepresent sound class of the ambient environment signals.
 23. The methodof claim 22, wherein determining the present sound class of the ambientenvironment signals comprises: determining a presence of speech in theambient environment signals; and classifying the ambient environmentsignals as speech signals, and wherein dynamically setting the MFO ofthe bone conduction device comprises: dynamically increasing the MFOonly when the ambient environment signals are classified as speechsignals.
 24. The method of claim 22, wherein determining the presentsound class of the ambient environment signals comprises: determining apresence of both speech and noise in the ambient environment signals;and classifying the ambient environment signals as speech and noisesignals, and wherein dynamically setting the MFO of the bone conductiondevice comprises: dynamically increasing the MFO only when the ambientenvironment signals are classified as speech and noise signals.
 25. Themethod of claim 22, wherein determining the present sound class of theambient environment signals comprises: determining a presence of musicin the ambient environment signals; and classifying the ambientenvironment signals as music signals, and wherein dynamically settingthe MFO of the bone conduction device comprises: dynamically increasingthe MFO only when the ambient environment signals are classified asmusic signals.
 26. The method of claim 21, wherein the bone conductiondevice comprises at least one battery, and wherein the method furthercomprises: monitoring a charge level of the at least one battery; anddynamically setting the MFO of the bone conduction device based on thepresent sound environment and the charge level of the at least onebattery.
 27. The method of claim 21, further comprising: determining apresent signal-to-noise ratio of the ambient environment signals; anddynamically setting the MFO of the bone conduction device based on theloudness of the present sound environment and the presentsignal-to-noise ratio of the ambient environment signals.
 28. The methodof claim 21, further comprising: wirelessly obtaining auxiliaryoperational data from the bone conduction device; and dynamicallysetting the MFO of the bone conduction device based the present soundenvironment and the auxiliary operational data.
 29. The method of claim28, wherein the auxiliary operational data includes at least one oftime-of-day information, location information, Global Positioning System(GPS) data, calendar information, user preferences, or user habitinformation.
 30. The method of claim 28, further comprising: determiningcurrent time-of-day information based on the auxiliary operational data;and dynamically setting the MFO of the bone conduction device based onthe present sound environment and the current time-of-day information.31. The method of claim 28, further comprising: determining a currentlocation of the bone conduction device based on the auxiliaryoperational data; and dynamically setting the MFO of the bone conductiondevice based on the present sound environment and the current locationof the bone conduction device.
 32. The method of claim 21, wherein thebone conduction device includes an actuator, and the method furthercomprises: generating, based on the present sound environment of theambient environment signals and the MFO, electrical signals for use indriving the actuator; and driving the actuator with the electricalsignals to deliver mechanical force to tissue of a user of the boneconduction device.
 33. The method of claim 32, wherein generating theelectrical signals for use in driving the actuator comprises:automatically adjusting a gain applied to the ambient environmentsignals based on the present sound environment of the ambientenvironment signals and the MFO of the bone conduction device.
 34. Themethod of claim 32, further comprising: band-pass filtering the ambientenvironment signals to generate band-pass filtered signals, wherein eachband-pass filtered signal is associated with a specific frequency rangeof the ambient environment signals; generating, for each of a pluralityof the band-pass filtered signals, corresponding electrical signals foruse in driving the actuator to evoke perception of the associatedfrequency range of the ambient environment signals; and individuallysetting the MFO of the bone conduction device based on a frequency rangeassociated with the corresponding band-pass filtered signal.
 35. Themethod of claim 21, wherein determining the present sound environmentcomprises: determining whether the bone conduction device is currentlyin a listening environment in which a user of the bone conduction devicecan benefit from higher output based on a sound class of the ambientenvironment signals.
 36. The method of claim 25, wherein dynamicallysetting the MFO of the bone conduction device comprises at least one of:dynamically increasing the MFO in response to determining that the boneconduction device is currently in a listening environment in which theuser can benefit from higher output; or dynamically decreasing the WO inresponse to determining that the bone conduction device is not currentlyin a listening environment in which the user can benefit from higheroutput.
 37. The method of claim 26, wherein dynamically increasing theWO in response to determining that the bone conduction device iscurrently in a listening environment in which the user can benefit fromhigher output comprises: temporarily increasing the MFO for apredetermined period of time or until a different sound class isdetected in the ambient environment signals.
 38. The method of claim 21,wherein dynamically setting the MFO of the bone conduction devicefurther comprises: terminating use of an increased MFO or decreasing theMFO based on one or more of a reduction in the loudness of the presentsound environment, a different sound class being detected in the ambientenvironment signals, a present signal-to-noise ratio of the ambientenvironment signals exceeding a threshold signal-to-noise ratio, apresent charge level of a battery of the bone conduction device beingbelow a threshold charge level, a change in auxiliary operational dataof the bone conduction device, or expiration of a predetermined periodof time.